JP3067160B2 - Communication control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention is used for a communication control device that is connected to a token passing bus and performs communication. The present invention relates to a communication control device that can determine a destination device when monitoring a status transmitted to a token passing bus.

〔Overview〕

The present invention relates to a communication control device that is connected to a token passing system bus and controls data communication. In a communication control device, among devices connected to the same bus, an identifier unique to each device (hereinafter referred to as ID) is added to a status and transmitted. By monitoring the status transmitted to the bus, it is possible to determine from which device the status is transmitted.

[Conventional technology]

In the conventional standard token bus system, among the data on the bus, data to which a special code called a SYNC code is added is treated as a control word. A device connected to the bus performs transmission based on the control word. Each device connected to the bus has one unique sequence number, and when a control word token having the same value as this sequence number appears on the bus, the corresponding device obtains the transmission right.

If there is data to be transmitted, the device that has obtained the transmission right inserts the data between the control word indicating the beginning of the data (hereinafter referred to as BOM) and the control word indicating the end of the data (hereinafter referred to as EOM) and inserts the data into the bus. Send out. At this time, a function code (hereinafter referred to as FC) indicating the data receiving destination is added to the BOM. When the device connected to the bus detects the BOM, it checks the FC and checks whether the data is the data to be received by itself. Confirm whether or not to receive the data.

A code is added to the EOM to determine whether or not to return a response to the data reception result. The device connected to the bus checks the EOM after receiving the data, and if there is a status response request, the status (hereinafter referred to as status) , STA). The STA contains the reception result of the received data and the sequence number of the receiving device.

At the end of the transmission or when there is no data to be transmitted, the device having the transmission right adds a value obtained by adding +1 to its own sequence number and transmits the token to the bus in order to pass the transmission right to another device.

When a device having the largest sequence number among the devices connected to the bus sends a token, there is no device having the same sequence number as the sequence number of this token, so the next token does not appear on the bus. If the token does not appear on the bus within the specified time (timeout), the device having the sequence number 0 obtains the transmission right.

The sequence number is set when the power is turned on or when a reset instruction is issued.

When each device does not receive a token addressed to itself during one cycle of the token, that is, between the time-out and the next time-out, the device decrements its own sequence number by one. Thus, when a missing number occurs in the sequence number due to a device failure or the like, the missing number is reduced and the token circulation is performed normally.

In addition, when a token is newly added during the circulation of the token, such as when the power is turned on, a timeout is awaited, and the sequence number of the token at the time of the timeout is set to the sequence number of the own device.

[Problems to be solved by the invention]

As described above, in the conventional device, the sequence number is
Depending on the number of devices at power-on and the order of power-on, different values will be obtained even for the same device. Further, when a sequence number is missing due to a device failure or the like, each device having a value larger than the sequence number of the failed device is
The sequence number is decremented by one so as to fill the missing number of the sequence number so that the sequence numbers are continuous.
For this reason, even if the status transmitted to the bus is monitored by a bus monitor or the like, it is not possible to know from which device the status is transmitted, and there is a disadvantage that it is not possible to efficiently evaluate the device or investigate a failure.

An object of the present invention is to solve such a problem, and an object of the present invention is to provide a device which can monitor which status is transmitted from a bus when monitoring the status transmitted to the bus.

[Means for solving the problem]

A first aspect of the present invention is a driver / receiver that is connected to a token passing bus and transmits and receives data to and from the token passing bus, a receiving circuit that processes the received token and data, a token, data, and a status. A communication control device comprising: a transmission circuit for transmitting data; a data processing circuit for processing transmission / reception data; and a control circuit for controlling each of the circuits, wherein the control circuit includes an ID number setting switch for setting an ID number. To
Means for adding the ID number set by the ID number setting switch to the status, and when receiving an instruction requiring a status response from the token passing bus,
Means for adding the set ID number to the reception result for the received message and transmitting the result as a status.

A second aspect of the present invention is a driver / receiver that is connected to the token passing bus and transmits and receives data to and from the token passing bus, a receiving circuit that processes the received token and data, a token, data, and a status. A communication control device comprising: a transmission circuit that transmits data, a data processing circuit that performs processing of transmission / reception data, and a control circuit that controls each of the circuits, comprising: an ID number storage register that holds an ID number; To
Means for storing the ID number added to the initial setting message transmitted at the time of system initialization in the ID number storage register, and when transmitting the status,
Means for adding the ID number stored in the ID number storage register to the status and transmitting the status.

It is desirable to assign the ID number in place of the sequence number of the standard status word.

[Action]

Attach to status when sending status
An ID number is set, and an ID number indicating that the ID number is unique among devices connected to the same token passing scheme bus is transmitted.

Also, an ID number that is unique to the devices connected to the same token passing scheme bus added to the initialization message transmitted at the time of system initialization is stored, and the ID stored when the status is transmitted. Add the number and send.

Thus, when the status transmitted to the bus is monitored, it is possible to determine from which device the status is transmitted, and it is possible to efficiently evaluate the device and investigate a failure.

〔Example〕

 Next, embodiments of the present invention will be described with reference to the drawings.

(First Embodiment) FIG. 1 is a block diagram showing a configuration of a first embodiment of the present invention.

In the first embodiment of the present invention, a driver / receiver 20 connected to a token passing system bus (hereinafter, referred to as a bus) 10 for transmitting / receiving data to / from the bus 10 and a receiving circuit 21 for processing a received token and data. And a transmitting circuit 22 for transmitting the token, data and status
A data processing circuit 23 for processing transmission / reception data, and a control circuit 25 for controlling each of the circuits, and an ID number setting switch 24 for setting an ID number.
25, means for adding the ID number set by the ID number setting switch 24 to the status, and when receiving an instruction requiring a status response from the bus 10, adds the set ID number to the reception result for the received message. Means for transmitting as a status.

Next, the operation of the first embodiment of the present invention configured as described above will be described.

First, as an initial setting, a unique value is set by the ID number setting switch 24 in a device connected to the token passing bus.

Next, when a BOM (control word representing the head of data) is received, the driver / receiver 20 sends the BOM to the receiving circuit 21. The receiving circuit 21 has received the BOM and added to the BOM.
The control circuit 25 is notified of the FC (function code).
The control circuit 25 having received the notification compares the notified FC with the FC to be received by the own device, and discards the message if they do not match. If they match, the message is received because the message is addressed to the own device.

When receiving the EOM (control word indicating the end of the message), the driver / receiver 20 sends the EOM to the receiving circuit 21. The receiving circuit 21 notifies the control circuit 25 of the reception of the EOM and a code added to the EOM indicating whether or not to make a status response. When the notified instruction has a status response, the control circuit 25 that has received the notification instructs the transmission circuit 22 to transmit the content of the ID number setting switch 24 and the reception result for the received message to the bus as a status. .

The transmission circuit 22 transmits the status to the bus via the driver / receiver 20 according to an instruction from the control circuit 25.
In addition, when the instruction is for no status response, the above operation is not performed.

(Second Embodiment) FIG. 2 is a block diagram showing a configuration of a second embodiment of the present invention.

The second embodiment of the present invention is connected to a bus 10,
A driver / receiver 20 for transmitting / receiving data to / from, a receiving circuit 21 for processing the received token and data, and a transmitting circuit for transmitting the token, data and status
22, a data processing circuit 23 for processing transmission / reception data,
A control circuit 25 for controlling each of the circuits, further comprising an ID
A means for storing an ID number added to an initialization message transmitted at the time of system initialization in the ID number storage register 26, and a status transmitted to the control circuit 25. Means for adding the ID number stored in the ID number storage register 26 to the status and transmitting the status.

Next, the operation of the second embodiment of the present invention will be described.

The communication control device 1 is connected to a bus 10 via a driver / receiver 20.

When receiving the initialization message, the driver / receiver 20 sends the initialization message to the receiving circuit 21. The receiving circuit 21 records the ID number added to the initial setting message.
It is sent to the ID number storage register 26. Further, the receiving circuit 21 notifies the control circuit 25 that the initial setting message has been received. The control circuit 25 that has received this notification initializes components other than the ID number storage register 26 in the communication control device 1.

When receiving a BOM (control word indicating the head of data), the driver / receiver 20 sends the BOM to the receiving circuit 21. The receiving circuit 21 has received the BOM and added to the BOM.
The control circuit 25 is notified of the FC (function code).
The control circuit 25 having received the notification compares the notified FC with the FC to be received by the own device, and discards the message if they do not match. If they match, the message is received because the message is addressed to the own device.

Next, when receiving the EOM (control word indicating the end of the message), the driver / receiver 20 sends the EOM to the receiving circuit 21. The receiving circuit 21 notifies the control circuit 25 of the reception of the EOM and a code added to the EOM indicating whether or not to make a status response.

When the notified instruction has a status response, the control circuit 25 that has received the notification instructs the transmission circuit 22 to transmit the contents of the ID number storage register 26 and the reception result for the received message to the bus as a status.

The transmission circuit 22 transmits the status to the bus via the driver / receiver 20 according to an instruction from the control circuit 25.
In addition, when the instruction is for no status response, the above operation is not performed.

FIG. 3 is a diagram showing the status of the communication control device in the embodiment of the present invention, and FIG. 4 is a diagram showing the status in the conventional example. STA in the figure is a code indicating that this communication data is a status.

In the status of the conventional device, only the reception result and the sequence number are added, but in the status of the present invention, the ID number is set at the position of the sequence number of the conventional device. This ID number is set to a value unique to each device among the devices connected to the same bus.

〔The invention's effect〕

As described above, according to the present invention, when the status transmitted to the bus is monitored by a bus monitor or the like by adding an ID number unique to each device to the status among the devices connected to the same bus, It is possible to know from which device the status has been transmitted, and therefore, there is an effect that the evaluation of the device and the failure investigation can be performed efficiently.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration of the first embodiment of the present invention. FIG. 2 is a block diagram showing the configuration of the second embodiment of the present invention. FIG. 3 is a diagram showing the status of the communication control device in the embodiment of the present invention. FIG. 4 is a diagram showing a status of a communication control device in a conventional example. DESCRIPTION OF SYMBOLS 1 ... Communication control device, 10 ... Token passing bus, 20 ... Driver / receiver, 21 ... Receiving circuit, 22 ...
... transmitting circuit, 23 ... data processing circuit, 24 ... ID number setting switch, 25 ... control circuit, 26 ... ID number storage register.

Claims (3)

(57) [Claims] 1. A driver / receiver connected to a token passing bus for transmitting and receiving data to / from the token passing bus, a receiving circuit for processing the received token and data, and transmitting the token, data, and status. A communication circuit comprising: a transmission circuit that performs transmission / reception data processing; and a control circuit that controls each of the circuits.The communication circuit includes an identifier number setting switch that sets an identifier number. Means for adding an identifier number set by the identifier number setting switch to a status, and when receiving an instruction requiring a status response from the token passing scheme bus, adding the set identifier number to a reception result for a received message. Means to send as status A communication control device which comprises. 2. A driver / receiver connected to a token passing bus, for transmitting and receiving data to and from the token passing bus, a receiving circuit for processing the received token and data, and transmitting the token, data, and status. A communication control device comprising: a transmission circuit that performs transmission / reception data processing; and a control circuit that controls each of the circuits.The communication control device further includes: an identifier number storage register that holds an identifier number. Means for storing an identifier number added to an initialization message transmitted at the time of system initialization in the identifier number storage register; and, when transmitting a status, the identifier number stored in the identifier number storage register is stored in a status. And means for transmission in addition to A communication control device to. 3. The communication control device according to claim 1, wherein the identifier number is assigned in place of the sequence number of the status word of the standard system.